The largest affluents are the Kassai on the left, and the Mobangi on the right bank; 110 m. are navigable to ocean steamers, then the cataracts intervene, and 250 m. of railway promote transit; the upper river is 2 to 4 m. broad, and navigable for small craft up to Stanley Falls, 1068 m.

Tracing the history of Italian painting is like pursuing a journey down an ever-broadening river, whose affluents are Giotto and Masaccio, Ghirlandajo, Signorelli, and Mantegna.